VMware’s VMTools package has some options for synchronizing the in-guest clock with the time of the ESXi host. By default, these are set to disabled, and under most circumstances, the hypervisor follows these settings and everything is fine. However, several situations exist where the hypervisor will reset the in-guest time, even though the VMTools setting…
Day: March 6, 2017
Using GROUP BY instead of DISTINCT
Recently, Aaron Bertrand (b/t) posted Performance Surprises and Assumptions : GROUP BY vs. DISTINCT. In it he says he prefers GROUP BY over DISTINCT. He discusses the fact that GROUP BY will, in fact, under certain circumstances, produce a faster query plan. I highly recommend taking the time to read it. In fact, if you…